1. Field of the Invention
The present invention relates to plumbing installations. More particularly, the invention concerns a dual flush system for a gravity flush toilet having an improved flush control apparatus.
2. Reference to Related Art
For many decades, household toilets have used a generally rectangular porcelain tank mounted above a porcelain bowl from which about 3.5 to 8 gallons of water are rapidly drained to flush waste from the bowl into a sewer system. One very common toilet design uses a silicon flapper that covers a single drain outlet located at the bottom of the tank. When a flush handle on the outside of the tank is manually depressed, the flapper valve is lifted and a modest pressure head of water in the tank empties through the drain outlet into the bowl. Typically, the flapper valve includes an inverted air chamber so that it initially floats as it is lifted away from the drain outlet. This floating flapper valve permits water to flow into the bowl even if the user immediately releases the flush handle. As the body of water flows through the drain outlet of the tank, it starts the siphoning action in the bowl and flushes the standing water in the bowl along with its waste contents into the sewer line.
A method for refilling the bowl and tank is also taught by the prior art. A ball cock valve or toilet tank fill valve mounted in the tank is connected to a pressurized water line in the house. When the tank drains, a float ball connected to the ball cock valve descends. The decent of the float ball opens the ball cock valve and begins the refilling of the tank.
When the tank is nearly empty, the flapper valve closes. The tank continues to fill as the float ball connected to the ball cock rises. At the same time, water from the ball cock valve enters an overflow tube to refill the bowl to a normal standing water level. Once the float ball reaches a predetermined height indicating the tank is full, the ball cock valve will close.
Water shortages throughout significant portions of the United States have forced major water conservation efforts. Conventional household toilets are wasteful and inefficient since a relatively large quantity of water is used to accomplish every flush. Therefore, various approaches have been employed in regions where water conservation is necessary to reduce water consumption by conventional toilets.
These efforts have led to improvements in toilets, such that as little as 1.6 gallons of water is utilized for a standard flush. However, this design is inefficient because while solid waste requires 1.6 gallons of water to accomplish the flush, liquid waste only requires enough water to replace the contaminated water in the bowl to complete the flush.
Additional approaches have included lowering the tank level or introducing a brick or dam to decrease the water volume released during each flush.
Yet another approach has been the development of a reduced flow (water saving) flapper valve that is designed with a vent in the air chamber portion of the flapper. The typical flush valve assembly (as discussed above) includes a single flapper valve having a normally downward opening air chamber which acts as a float when the flapper is raised off its seat to hold the flapper valve open when water is in the tank. A reduced flow flapper allows air to escape when in the open position allowing a rapid descent of the flapper. Therefore, the inlet is sealed before the entire contents of the tank are emptied into the bowl and the amount of water dispensed during each flush is effectively decreased. This approach has also been generally unsatisfactory because the consequent reduction in water flow into the bowl often results in incomplete flushing of solid waste. Users then flush twice, compounding the waste of water.
Still another approach for conserving water in toilets has been the use of multi-level flush valves. These valves comprise one inlet at or near the base of a toilet tank for long (solid waste) flushes and another inlet set at a higher elevation in the tank for short (liquid waste) flushes. Such devices depend on the depth of the water to be consistent within the tanks in which they are installed. However, in view of the variety of toilet designs available, each having a different shape or size tank, this approach is ineffective.
Accordingly, it is desirable that an improved dual flush apparatus be available which is simple, effective and adaptable for use in a variety of tank shapes and sizes while adequately providing for both long and short flushes of a toilet, with maximum efficiency for the volume of water used.
A dual inlet flush valve system is designed to replace standard flush valves and handles without the need for modification of the toilet tank or bowl. This invention provides the public with a simple and inexpensive device that allows the user to easily manage the amount of water dispensed per each flush while at the same time effectively providing for both solid and liquid waste flushes thus minimizing water consumption.
To achieve this, a flush valve system has been developed that is designed to utilize standard size flapper valves, seals and retainer nuts that are readily available at most plumbing retailers. It is preferably constructed of a single housing unit having at least two inlets affixed near the base of the tank fluidly connecting a single outlet. A flush handle assembly includes at least two handles mechanically connected to and at least two linkages. Both linkages pass through a sleeve assembly, which mounts in the standard mount hole provided on conventional gravity flush toilet tanks to provide effective control for the dual inlet flush valve. The inlets are sealed with a primary and a secondary flapper valve that are preferably connected by a chain or other link to the at least two linkages. The first (primary) flapper is preferably a reduced flow (water saving) flapper for use in flushing of liquid waste. The second (secondary) flapper is preferably a standard flapper for use in flushing solid waste or a combination of liquid and solid waste.